In this study, essential oils (EO) of Ocimum gratissimum L., Ocimum basilicum L. (basil) and Rosmarinus officinalis L. (rosemary) originated in Vietnam were extracted by using steam distillation method. GC/MS analysis indicated that the major components in O. gratissimum EO: Eugenol (68.7 %), cis-β-Ocimene (8.2 %), D-Germacrene (11.7 %) and others. O. basilicum EO: Estragole (84.8 %), trans-α-Bergamotene (2.7 %), Linalool (1.9 %) and Rosemarinus officinalis EO: D-α-Pinene (22.1 %), Eucalyptol (17.0 %) and Verbenone (14.9 %). The results showed that the antioxidant ability of O. gratissimum EO by DPPH method and ABTS method have the highest value of IC50. In DPPH method, IC50 of O. gratissimum EO is 5.1 (µg/ml), IC50 of O. basilicum EO is 18.2 (µg/ml), IC50 of Rosemarinus officinalis EO is 42.0 (µg/ml), which are lower than that of Vitamin C (IC50 = 4.8 (µg/ml) as control sample. In ABTS method, IC50 of O. gratissimum EO = 2.9 (µg/ml), IC50 of O. Basil EO = 10.4 (µg/ml), IC50 of Rosemary EO = 42.8 (µg/ml), which are lower than that of Vitamin C (IC50 = 2.3 (µg/ml)) as control sample.

This study was conducted to investigate the factors affecting on micr drying method. Various parameters were clearly investigated including concentrations of maltodextrin as wall material (20% 30 %), concentration of essential oils (0.5% temperature (130 -140 ), and feed flow rate (from 4 ml/min to 10 ml/min). The suitable conditions were the maltodextrin concentration of 25% (w/w), the concentration of essential oil of 1.5% (w/w), roto , and feed drying rate of 6 ml/min. The microencapsulation efficiency and the microencapsulation yield were 94.68% and 80.74%, respectively.